JPH03249759A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To provide the photosensitive body having a particularly excellent electrophotographic sensitive at the time of positive electrostatic charge by using a pyrylium dye, electrically insulating polymer and specific compd. as essential components. CONSTITUTION:This photosensitive body contains the pyrylium dye, the electrically insulating polymer and the compd. expressed by formula I on a conductive base body. In the formula I, R<1> and R<2> denote a hydrogen atom, amino group; R<3> and R<4> denote a hydrogen atom, alkoxy group, etc.; Ar denotes a substd. or unsubstd. monocyclic arom. hydrocarbon group, substd. or unsubstd. non- condensed polycylic arom. hydrocarbon group, etc. The photosensitive body having the excellent electrophotographic sensitivity, more particularly the extremely high electrophotographic sensitive at the time of the positive electrostatic charge is obtd. in this way.

Description

[Detailed description of the invention] 〔Technical field〕 The present invention relates to an electrophotographic photoreceptor.

The photoreceptor of the present invention can also be laminated as a first photoreceptor layer with another first and second photoreceptor layer to form a composite photoreceptor for electrophotography (for two-color process).

[Conventional technology]

Electrophotographic photoreceptors with a photoconductive layer made of a composition containing a eutectic complex consisting of a pyrylium dye and an electrically insulating polymer and, if necessary, a triphenylmethane sensitizer, are known (for example, Publication No. 46-22518, 46-22
Publication No. 519, Publication No. 51-1129, Japanese Unexamined Patent Publication No. 1977-
No. 10785, No. 51-88226, No. 51
-93324, 53-87227, etc.).

Although these photoreceptors have electrophotographic sensitivity that is acceptable for practical use, they have not yet reached a level of sufficient sensitivity residual potential.

〔the purpose〕

An object of the present invention is to provide an electrophotographic photoreceptor having extremely excellent electrophotographic sensitivity.

More specifically, the object is to provide an electrophotographic photoreceptor that has particularly excellent electrophotographic sensitivity when positively charged.

Another object of the present invention is to provide an electrophotographic photoreceptor that can be easily manufactured.

〔composition〕

The present invention relates to an electrophotographic photoreceptor characterized in that the main components are a pyrylium dye, an electrically insulating polymer, and a compound represented by the following general formula (1) on a conductive substrate.

(In the formula, R1 and R2 are a hydrogen atom, an amino group, a substituted or unsubstituted dialkylamino group, an alkoxy group, a thioalkoxy group, an aryloxy group, a substituted or unsubstituted alkyl group, a halogen atom, or a substituted or unsubstituted dialkylamino group) , R3 and R4 represent a hydrogen atom, an alkoxy group, a substituted or unsubstituted alkyl group, or a halogen atom. Ar is a substituted or unsubstituted monocyclic aromatic hydrocarbon group, a substituted or unsubstituted non-fused (represents a polycyclic aromatic hydrocarbon group or a substituted or unsubstituted heterocyclic group).

The present invention will be described in detail below with reference to the drawings.

FIG. 1 is a sectional view showing an example of the structure in which the electrophotographic photoreceptor of the present invention is used, in which a eutectic complex photosensitive layer 15 made of the photoreceptor of the present invention is provided on a conductive substrate 11.

FIG. 2 shows another configuration example of the present invention, in which the conductive substrate 11
A subbing layer 14 is provided between the photoreceptor and a eutectic complex photosensitive layer 15 made of the photoreceptor of the present invention.

Further, FIG. 3a shows a composite photoreceptor for electrophotography using the photoreceptor of the present invention. A photosensitive layer 12 (hereinafter referred to as a second photosensitive layer) sensitive to light transmitted through a eutectic complex photosensitive layer 15 made of the photoreceptor of the present invention is provided on a conductive substrate 11,
Furthermore, a eutectic complex photosensitive layer 15 is provided thereon.

FIG. 3 shows another structural example of a composite photoreceptor for electrophotography, in which an intermediate layer 13 is provided between the second photosensitive layer 12 and the eutectic complex photosensitive layer 15 made of the photoreceptor of the present invention. It is something that has been established.

The conductive substrate 11 is made of a material 5 that exhibits conductivity with a volume resistance of 1010 Ω1 or less, for example, aluminum.

Metals such as nickel, chromium, nichrome, copper, silver, gold, and platinum, and metal oxides such as tin oxide and indium oxide,
Film-like or cylindrical plastic or paper coated by vapor deposition or sputtering, or plates made of aluminum, aluminum alloy, nickel, stainless steel, etc., and their coatings; 1. ．． 1.1. It is possible to use pipes that have been made into blank pipes by methods such as , extrusion, and drawing, and then surface-treated by cutting, superfinishing, polishing, and the like.

As mentioned above, the eutectic complex photosensitive layer 15 includes a eutectic complex,
It is formed mainly of a conductive substance represented by the general formula (1). The eutectic complex here is made from a pyrylium dye and an electrically insulating polymer.

The compound of general formula (I) is preferably blended into the polymer in advance.

There are three types of pyrylium dyes: pyrylium salts, thiapyrylium salts, and selenapyrylium salts, and they have the following general formula.

In the above formula, Ra, Rb, Ro, Rd and R8Ll each represent (a) a hydrogen atom, (b) an alkyl group, typically methyl, ethyl, propyl, isopropyl, butyl, t-butyl, amyl, isoamyl, C-C15 alkyl groups such as hexyl, octyl, nonyl and dodecyl; (C) alkoxy groups such as methoxy, ethoxy, propoxy, butoxy, amyloxy, hexoxy and octoxy;

(d) Alkylphenylxyphenyl such as phenyl, 4-diphenyl, 4-ethylphenyl, 4-propylphenyl, 4-amyloxyphenyl, 2-hexoxyphenyl, 2-methoxyphenyl, 3,4-dimethoxyphenyl, etc. Flucoxyphenyls; β-hydroxyalkoxyphenyls such as 2-hydroxyethoxyphenyl and 3-hydroxyethoxyphenyl; 4-hydroxyphenyl, 2,4-dichlorophenyl, 3.4-
Halophenyls such as dibromophenyl, 4-chlorophenyl, 3,4-dichlorophenyl; azidophenyl,
Aminophenyls such as nitrophenyl, 4-diethylaminophenyl, 4-dimethylaminophenyl; naphthyl.

Styryl, methoxystyryl, jetoxystyryl, dimethylaminostyryl, 1-butyl-4-p-dimethylaminophenyl-1,3-butadienyl, β-ethyl-
Aryl groups including substituted aryl groups such as vinyl substituted aryl groups such as 4-dimethylaminostyryl.

, X is a sulfur, oxygen, or selenium atom, and Z- is an anion such as perchlorate, fluoroborate, iodide, chloride, bromide, sulfate, chloride, p-toluenesulfonate, hexafluorophosphate, etc. It is an ionic functional group.

R', Rb, R', Rd, and Re may be atoms necessary to jointly complete the aryl ring fused to the pyrylium nucleus.

Representative examples of such pyrylium dyes are shown below.

5 2,4,6-driphenylpyrylium perchlorate 4 2,4,6-triphenylpyrylium fluoroborate diphenylpyrylium fluoroborate 44 2,4,6-driphenylthiapyrylium perchlorate 4 2,4・6-driphenylthiapyrylium sulfate 6 2,4,6-driphenylthiapyrylium chloride 4 2,4,6-drianisylthiapyrylium perchlorate 5 6-Nithyl-2,4-diphenylpyrylium fluoroborate Selenavirylium Chlorate S-Chlorate Particularly useful pyrylium dyes are those having the following formula:

In the formula, R1 and R2 are alkyl groups of 01 to CG and 01 to
an aryl group such as a substituted phenyl group having at least one substituent selected from C6 alkoxy groups,
R3 is an alkylamino-substituted phenyl group in which the alkyl moiety is C□ to C6, and may also be a dialkylamino-substituted or haloalkylamino-substituted phenyl group. X is an oxygen, sulfur or selenium atom, and Z- is as described above.

Any electrically insulating polymer can be used as the electrically insulating polymer, but those having an alkylidene diarylene moiety represented by the following formula in the main chain (repeating unit) are particularly useful.

(Margin below) R.

In the formula, R4 and Rs are methyl, ethyl, propyl, isopropyl, and butyl, respectively, containing a hydrogen atom and a substituted alkyl group such as trifluoromethyl.

Alkyl groups such as t-butyl, pentyl, hexyl, heptyl, octyl, nonyl, decyl, halogen, C1~
Aryl groups such as phenyl and naphthyl, including substituted aryl groups having a substituent such as an alkyl group at C5, and R4 and R5 jointly represent cycloalkanes such as cyclohexyl and polycycloalkanes such as norbornyl. R6 and R1 may be carbon atoms necessary to form a cyclic hydrocarbon group containing hydrogen, C□ to C
1 is an alkyl group or a halogen such as chloro, bromo, or iodine, and R1 is.

It is a divalent group.

Hydrophobic carbonate polymers (polycarbonates) comprising repeating units of the following formula are also useful and preferred.

R6 In the formula, R is a phenylene group including halo-substituted phenylene groups and alkyl-substituted phenylene groups, and R6 and R5 are as described above. These polymers are USP3,
No. 028,365 and No. 3,317,466. Preferably, the polymer comprises a polymer containing an alkylidene diarylene moiety in the repeating unit and produced by transesterification between diphenyl carbonate and 2,2-bis(4-hydroxyphenyl)propane, such as those made from bisphenol A. Polycarbonates are useful. Such polymers are listed in USP 2,999,750
No. 3,038,874, No. 3,038,880, No. 3,106゜544, No. 3,106,545,
It is disclosed in No. 3,106,546, etc. In any case, film-forming polycarbonate resins can be used in a wide variety of ways.

Satisfactory results are obtained especially when using those having an intrinsic viscosity of about 0.5 to 1.8.

Specific examples of the electrically insulating polymer are as follows.

Thiocarb fuichitofu (4-phenylenecarbohydrate) -bonato) Len) Also, Representative examples of the compound represented by general formula (1) are shown below.

(Left below) In order to make the eutectic complex photosensitive layer 15 of the present invention, the above pyrylium dye, the electrically insulating polymer, and the formula (I) are used.
The compound represented by is dissolved in a suitable solvent such as tetrahydrofuran, toluene, 1,2-dichloroethane, methylene chloride, chloroform, monochlorobenzene, dichlorobenzene, benzene, etc., and this is added to conductive substrate 1.
1 and dried at 50-130℃ to obtain a film thickness of 5-5.
A photoconductive layer (eutectic complex photosensitive layer) 15 having a thickness of 0 μm may be formed.

Application can be carried out using a dip coating method, a bead coating method, a spray coating method, a wire blade, a doctor blade, an air knife, or the like.

During this coating and drying process, a eutectic complex is formed between the pyrylium dye and the electrically insulating polymer.

The ratio of each component in the eutectic complex photosensitive layer 15 is 5 to 80 parts by weight of the electrically insulating polymer to 1 part by weight of the pyrylium dye.
Parts by weight, -1 to 50 parts by weight of the compound represented by formula (I) are suitable.

Further, when forming this layer 15, a leveling agent such as silicone oil may be added to the coating liquid. The appropriate amount to be used is about O-1% by weight based on the electrically insulating polymer.

Furthermore, when providing the layer 15, a binder is used as necessary.

The binder used here is polyethylene, polystyrene, polybutadiene, styrene-butadiene copolymer, polymers and copolymers of acrylic ester or methacrylic ester, polyester, polyamide, epoxy resin, urethane resin, silicone resin, alkyd. Resin, cellulose resin, poly-N-vinylcarbazole and its derivatives (for example, those having a halogen such as chlorine or bromine, or a substituent such as a methyl group or an amino group in the carbazole core), polyvinylpyrene, polyvinylanthracene, pyrene- Formaldehyde condensation polymers and derivatives thereof (for example, those having substituents such as halogen such as bromine and nitro group in the pyrene core), poly γ-carbazolylethyl-L-daltamate, styrene resin, chlorinated polyethylene, acetal resin, Examples include melamine resin.

A plasticizer can be used in combination with this binder. Plasticizers that are commonly used as plasticizers for resins include dibutyl phthalate and dioctyl phthalate.
It can be used as is.

The appropriate amount to be used is about 0 to 30% by weight based on the binder.

In addition, when forming the eutectic complex photosensitive layer 15 of the present invention, the method of overcoating the coating liquid (Japanese Unexamined Patent Publication No. 56-40837) or the method of applying pyrylium dye to the electrically insulating polymer layer that has already been formed may be used. Method of drying after soaking (Japanese Patent Application Laid-Open No. 56-8005
(Japanese Patent Application Laid-open No. 121042/1982) may be used, or the concentration of the pyrylium dye in Calendar 15 may be made different on the conductive substrate side and near the surface (Japanese Patent Laid-Open No. 121042/1983). good.

In the present invention, as shown in FIG. 2, a conductive substrate;
By providing the subbing layer 14 between the eutectic complex photosensitive layers, charging properties and adhesion properties can be improved.

The undercoat layer 14D may be made of an inorganic material such as Sin, AQ, O, etc., provided by a method such as vapor deposition, sputtering, or anodization, or may be made of polyamide resin, alcohol-soluble nylon resin,
A resin layer made of water-soluble polyvinyl butyral resin, polyvinyl butyral resin, etc. can be used.

Furthermore, a resin undercoat layer in which pigment particles such as ZnO, TiO□, ZnS, etc. are dispersed can also be used as the undercoat layer.

Furthermore, a silane coupling agent, a titanium coupling agent, a chromium coupling agent, etc. can also be used as the subbing layer 14 of the present invention.

The thickness of the undercoat layer 14 is suitably 0 to 5 μm.

Further, in the present invention, it is also possible to provide a protective layer or an insulating layer on the eutectic complex photosensitive layer 15.

The protective layer is provided for the purpose of protecting the surface of the photoreceptor, and materials used for this include ABS resin, AC8 resin, olefin rubinyl monomer copolymer, chlorinated polyether,
Allyl resin, phenolic resin, polyacetal, polyamide, polyamideimide, polyacrylate, polyallyl sulfone, polybutylene, polybutylene terephthalate, polycarbonate, polyether sulfone, polyethylene, polyethylene terephthalate, polyimide, acrylic resin, polymethylpentene, polypropylene, polyphenylene Nylene oxide, polysulfone, polystyrene,
Examples include resins such as AS resin, butadiene-styrene copolymer, polyurethane, polyvinyl chloride, and polyvinylidene chloride epoxy resin. In addition, the protective layer may include fluororesins such as polytetrafluoroethylene, silicone resins, and inorganic materials such as titanium oxide, tin oxide, potassium titanate, etc. dispersed in these resins for the purpose of improving wear resistance. Can be added. A normal coating method is adopted as a method for forming the protective layer. The thickness of the protective layer is 0.5
~10 μm is appropriate.

For the insulating layer, the binder that may be used in the eutectic complex photosensitive layer mentioned above can be used as is, or it can be provided by applying a solution containing the binder.

In addition, heat shrink films such as polyvinyl chloride, polypropylene, polyester, polystyrene, polyvinylidene chloride, polyethylene, chlorinated rubber, Teflon, etc.
Tubes can also be used.

As an example embodiment of the invention, FIG. 3a.

An example is a composite photoreceptor for electrophotography as shown in FIG.

For the second photosensitive layer 12 and the intermediate layer 13, known materials (for example, JP-A-56-121044) can be used, and for the first photosensitive layer, the above-mentioned eutectic complex photosensitive layer 15 can be used. I can do it.

Images can be formed on the composite photoreceptor for electrophotography thus obtained by applying a known process (for example, Japanese Patent Application Laid-open No. 121044/1983).

2 4-(4-dimethylaminophenyl)-2,6-3 parts by weight Diphenylthiapyrylium barchlorate polycarbonate 28 parts by weight (Panlite L-1250 manufactured by Konjin Kasei Co., Ltd.) Methylene chloride
650 parts by weight CH.

A coating solution having the following composition was applied onto a polyethylene terephthalate film on which AQ was vapor-deposited and dried to form a eutectic complex photosensitive layer with a dry film thickness of 16 μm.

Takuji Magasa, except that a compound of the following structural formula was used instead of the compound of formula (1) in Example-1.

A photosensitive layer was formed in the same manner as in Example-1.

The photoreceptor obtained as described above was attached to an electrostatic paper analyzer (SP-428 newly manufactured by Kawaguchi Electric Co., Ltd.), and the corona discharge pressure was -5.5K.
V or +6. Potential Vm after 10 seconds of charging with OKV (
V), potential Vo (V) after 10 seconds of dark decay, intensity 10 l
Residual potential V * (V) after 15 seconds of exposure in ux, and the exposure amount E required to further attenuate the potential Vo to 115
115 (lux-secl was measured.

The potential retention rate is defined as follows.

m Further, charging and exposure under the above conditions were carried out continuously for one hour at the same time to fatigue the photoreceptor, and then the characteristics of the photoreceptor were further measured in the same manner as above.

The results are shown in Table 1-.

Table 1 A photosensitive layer was formed in the same manner as in Example 1 except that the compound shown in Table 2 was used instead of the compound of formula (1) in Example 1.

Table 2 shows the measurement results of photoreceptor characteristics.

(The following is a blank space) Table 2: V A subbing layer coating liquid and a eutectic complex photosensitive layer coating liquid having the following compositions were applied on an AU punched plate with a thickness of 0.2 mm, dried, and the subbing layer was coated. (film thickness 0.3 μm) and eutectic complex photosensitive layer (film thickness 15 μm)
m) to produce the electrophotographic photoreceptor shown in FIG.

(1) Undercoat layer coating liquid ethanol 300 parts by weight (2
) Eutectic complex photosensitive layer coating liquid Compound of formula (1) shown in Table 3 25 parts by weight Methylene chloride 500 parts by weight Chloroform 150 parts by weight Instead, photoreceptors were prepared in the same manner as in Examples 8 to 14, except that the triphenylmethane compound used in Comparative Example 1 was used.

Table 3 shows the measurement results of photoreceptor characteristics.

(Margin below) 〔effect〕 According to the present invention (1) A new electrophotographic photoreceptor could be provided.

(2) A photoreceptor having excellent electrophotographic sensitivity, particularly extremely high electrophotographic sensitivity when positively charged, could be provided.

(3) An electrophotographic photoreceptor with low residual potential could be provided.

[Brief explanation of drawings]

FIGS. 1 to 3a and 3b are cross-sectional views showing an example of the structure of an electrophotographic material using the electrophotographic photoreceptor of the present invention. 11... Conductive substrate 12... Second photosensitive layer 13
... Intermediate layer 14 ... Subbing layer 15 ... Eutectic complex photosensitive layer

Claims (1)

[Scope of Claims] 1. An electrophotographic photoreceptor characterized by containing as main components a pyrylium dye, an electrically insulating polymer, and a compound represented by the general formula (I). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R^1 and R^2 are hydrogen atoms, amino groups, substituted or unsubstituted dialkylamino groups, alkoxy groups,
A thioalkoxy group, an aryloxy group, a substituted or unsubstituted alkyl group, a halogen atom, a substituted or unsubstituted aryl group, and R^3 and R^4 are a hydrogen atom, an alkoxy group, a substituted or unsubstituted alkyl group, or Represents a halogen atom. Ar represents a substituted or unsubstituted monocyclic aromatic hydrocarbon group, a substituted or unsubstituted non-fused polycyclic aromatic hydrocarbon group, or a substituted or unsubstituted heterocyclic group. )